Outback's Inland Sea Offers Greenhouse Gas Hunt Chance

American PhD candidate Stony Samberg is right at home in Australia's outback. The Wyoming-born researcher is leading Southern Cross University's field experiments in the desert to determine how much carbon dioxide, methane and nitrous oxide is released in dryland floodplains under dry and flooded conditions.

The heart of Australia's ancient, arid interior is a place of dramatic contrasts. Cyclone Alfred's arrival in March 2025 delivered record-breaking rains over Queensland's Channel Country, devastating outback towns like Quilpie, Jundah, and Thargomindah while transforming the dry and dusty floodplains into waterways as far as the eye can see. Now these floodwaters are flowing inland, filling up the endorheic Kati Thanda-Lake Eyre (KTLE) in South Australia's far north and replacing the normally salt-crusted basin with an outback oasis teeming with life – plants, fish, shrimp and migratory birds.

"There is just an overwhelming volume of water on the Channel Country floodplains, nearly 50km wide in some areas. These truly different changes in the state of the land, from dry to wet, that's the kind of comparisons we're looking for," said Stony Samberg, who's just returned to Lismore after completing his fourth trip to the outback in 12 months.

"By the time I go out again at the end of July, there should be much more vegetation on the floodplain, it should be a really stark contrast. I feel privileged to witness it."

Stony's efforts to measure greenhouse gas flux within the KTLE Basin are contributing to the ARC Discovery Project awarded to his supervisor Professor Bradley Eyre, 'Resolving the role of dryland flooding in the global carbon cycle' (DP220100918).

Millions of litres of water sit on dryland floodplains every few years and yet its contribution to the global carbon cycle remains largely unknown. Professor Eyre and Stony's research aims to determine whether flooded drylands release large amounts of carbon dioxide, methane and nitrous oxide, which may account for some of the planet's missing sources of methane and inform future earth system climate models and management of the global carbon cycle.

The data is also be used by PhD candidate Anju Rana to develop a process model of the KTLE Basin to predict greenhouse gas emissions under current dry and flooded conditions and future climate change scenarios.

"We are measuring greenhouse gas fluxes – the emission and consumption of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) across the KTLE basin. By doing so we will fill existing knowledge gaps about what controls greenhouse gas flux and update current flux estimates," said Stony.

With the help of other PhD students and academic advisors, Stony is taking samples from national parks, crown land and private land in 12 different locations across the KTLE basin, in both dry and wet conditions – with the permission and assistance of Indigenous rangers, Traditional Owners and pastoralists.

Small acrylic chambers attached to stainless steel collars are placed in different areas of the landscape (upland, floodplain, river channel/lakebed). Diurnal (day/night) measurements are taken over the course of 24 hours to capture the range of greenhouse gas flux at different times of the day. As well, 500-grams of sediment from each chamber is collected to analyse secondary characteristics like soil texture, bulk density, aggregate size, and organic carbon and inorganic carbon content.

"In combination with weather data (temperature, humidity, barometric pressure) collected at the same time, we can evaluate what environmental factors are associated with the greatest flux of greenhouse gases," he said.

While the KTLE basin is used to cultivate livestock, human impact is minimal, observed Stony.

In addition, it is one of the only unregulated major river systems in the world, with no large dams or water extractions.

"It's a mostly pristine environment for measuring these naturally occurring greenhouses gases," he said.

"The population out here is small, so the anthropogenic impact is minimal. Essentially there is no baseline for these areas in terms of what kind of natural variation exists for greenhouse gas emissions because it's so remote. Until now, there's just not been a lot of scientific interest in these arid environments.

"We've had the opportunity to establish a baseline of greenhouse gas flux in the dry state and now can compare it to the flux in a wet state. This research builds on Bradley's initial work at KTLE when it was in flood in 2019 that showed globally significant emissions of greenhouse gases."

From Wyoming to Australia's outback

With an undergraduate degree in botany and a Masters in environmental science focused on wetland nutrient cycling, Stony jumped at the opportunity to relocate 'down under' to pursue a doctoral thesis under the supervision of Professor Eyre.

"I was well aware of the impact of Brad's research," said Stony.

"The PhD at Southern Cross was an opportunity to switch from looking at water and plants to looking at gases in an environment completely different than what I've researched before. At the same time I was coming from a fairly remote area of the US, in the state of Wyoming where you drive hours to get anywhere, just like you would in Australia."

Wyoming is located in the Mountain West region of the western United States. The landlocked state is semi-arid and known for its grasslands and mountains. Stony grew up exploring and camping all over Wyoming.

"I knew I could definitely handle working and living in Australia's remote places. While a lot of Southern Cross students excel in the marine environment, scuba diving and so on, I thought I could make an impact in a harsh, inland environment. I could go out there and really thrive.

"When you're out in the desert and you're swamped by 1000 flies and it's 40°-plus Celsius and you're hours away from the next person …. where can you find a bright spot? Well, you know, I'm seeing things that nobody else is seeing. I'm in an area that very few people get to spend their time.

"The nights are just magnificent. You see so many stars and once those flies and bugs quieten down, it's just beautiful. And I got to say the sunrises and sunsets these big open skylines, it's breathtaking."

"I don't want to say it's uncomfortable in the outback. It's a bit strange, but in that sense it feels very much like home."

Acknowledgements

This research would not have been possible without the generous help of:

• Academic advisors: Professor Bradley Eyre; Professor Judith Rosentreter; Dr Jacob Yeo.
• PhD candidates: Ryan Felton; Anju Rana; Leslie Galstaun; Abby Webster.
• As well as meaningful contributions from the Arabana Aboriginal Company; Mithaka Aboriginal Company; and Queensland Parks and Wildlife Service.
• Funding from the Australian Research Council (DP220100918).